Use Jacoco to create a code coverage report; update build scripts to run it.
Use Jacoco to create a code coverage report; update build scripts to run it.

Summary:
We used to measure code coverage with EMMA, but it proved to be too flaky to
run on every build. This diff introduces a script to measure it with Jacoco:

```
buck test --all --code-coverage --code-coverage-format xml --no-results-cache
python scripts/assert_code_coverage.py
```

The script prints out a summary of code coverage by package to the console.
It returns with a non-zero exit code if code coverage by line drops below 78%.
Currently, we are at 81.06%, so hopefully we can maintain this (or even better,
crank it up over time).

zpao/buck,zhan-xiong/buck,facebook/buck,mikekap/buck,justinmuller/buck,ilya-klyuchnikov/buck,rowillia/buck,Learn-Android-app/buck,zpao/buck,davido/buck,Addepar/buck,pwz3n0/buck,artiya4u/buck,neonichu/buck,vschs007/buck,Heart2009/buck,vine/buck,rhencke/buck,bocon13/buck,brettwooldridge/buck,dsyang/buck,illicitonion/buck,shs96c/buck,LegNeato/buck,justinmuller/buck,OkBuilds/buck,liuyang-li/buck,rowillia/buck,rowillia/buck,LegNeato/buck,sdwilsh/buck,Distrotech/buck,marcinkwiatkowski/buck,janicduplessis/buck,LegNeato/buck,rmaz/buck,Learn-Android-app/buck,hgl888/buck,stuhood/buck,clonetwin26/buck,brettwooldridge/buck,hgl888/buck,darkforestzero/buck,shybovycha/buck,Addepar/buck,liuyang-li/buck,dsyang/buck,illicitonion/buck,mnuessler/buck,ilya-klyuchnikov/buck,luiseduardohdbackup/buck,janicduplessis/buck,tgummerer/buck,bocon13/buck,nguyentruongtho/buck,rowillia/buck,tgummerer/buck,zhuxiaohao/buck,hgl888/buck,bocon13/buck,OkBuilds/buck,MarkRunWu/buck,zhuxiaohao/buck,illicitonion/buck,bocon13/buck,dushmis/buck,tgummerer/buck,rhencke/buck,SeleniumHQ/buck,dpursehouse/buck,Dominator008/buck,LegNeato/buck,Heart2009/buck,liuyang-li/buck,lukw00/buck,kageiit/buck,mogers/buck,marcinkwiatkowski/buck,justinmuller/buck,robbertvanginkel/buck,grumpyjames/buck,mogers/buck,lukw00/buck,sdwilsh/buck,robbertvanginkel/buck,vine/buck,SeleniumHQ/buck,artiya4u/buck,JoelMarcey/buck,1yvT0s/buck,shybovycha/buck,saleeh93/buck-cutom,SeleniumHQ/buck,SeleniumHQ/buck,siddhartharay007/buck,SeleniumHQ/buck,shybovycha/buck,brettwooldridge/buck,romanoid/buck,raviagarwal7/buck,rmaz/buck,ilya-klyuchnikov/buck,liuyang-li/buck,romanoid/buck,marcinkwiatkowski/buck,dsyang/buck,JoelMarcey/buck,bocon13/buck,raviagarwal7/buck,davido/buck,tgummerer/buck,brettwooldridge/buck,romanoid/buck,vine/buck,mogers/buck,1yvT0s/buck,k21/buck,Learn-Android-app/buck,grumpyjames/buck,zhan-xiong/buck,davido/buck,shybovycha/buck,pwz3n0/buck,facebook/buck,JoelMarcey/buck,justinmuller/buck,liuyang-li/buck,rmaz/buck,daedric/buck,pwz3n0/buck,Learn-Android-app/buck,zhuxiaohao/buck,JoelMarcey/buck,ilya-klyuchnikov/buck,stuhood/buck,justinmuller/buck,dushmis/buck,robbertvanginkel/buck,kageiit/buck,clonetwin26/buck,grumpyjames/buck,mogers/buck,janicduplessis/buck,mikekap/buck,janicduplessis/buck,shybovycha/buck,nguyentruongtho/buck,Learn-Android-app/buck,shybovycha/buck,rhencke/buck,SeleniumHQ/buck,justinmuller/buck,marcinkwiatkowski/buck,JoelMarcey/buck,dsyang/buck,tgummerer/buck,ilya-klyuchnikov/buck,robbertvanginkel/buck,justinmuller/buck,luiseduardohdbackup/buck,raviagarwal7/buck,1yvT0s/buck,vine/buck,vschs007/buck,MarkRunWu/buck,LegNeato/buck,clonetwin26/buck,mikekap/buck,Distrotech/buck,dsyang/buck,justinmuller/buck,grumpyjames/buck,dsyang/buck,mogers/buck,ilya-klyuchnikov/buck,brettwooldridge/buck,davido/buck,zhuxiaohao/buck,k21/buck,marcinkwiatkowski/buck,zpao/buck,Dominator008/buck,luiseduardohdbackup/buck,Distrotech/buck,mnuessler/buck,Dominator008/buck,mikekap/buck,dsyang/buck,mogers/buck,mikekap/buck,mnuessler/buck,daedric/buck,justinmuller/buck,clonetwin26/buck,vschs007/buck,davido/buck,JoelMarcey/buck,zpao/buck,mread/buck,SeleniumHQ/buck,mread/buck,Addepar/buck,facebook/buck,liuyang-li/buck,marcinkwiatkowski/buck,daedric/buck,bocon13/buck,dpursehouse/buck,k21/buck,davido/buck,shybovycha/buck,justinmuller/buck,darkforestzero/buck,rowillia/buck,shs96c/buck,LegNeato/buck,Learn-Android-app/buck,romanoid/buck,sdwilsh/buck,hgl888/buck,JoelMarcey/buck,brettwooldridge/buck,Distrotech/buck,SeleniumHQ/buck,vine/buck,romanoid/buck,davido/buck,sdwilsh/buck,zhuxiaohao/buck,OkBuilds/buck,siddhartharay007/buck,zhan-xiong/buck,illicitonion/buck,OkBuilds/buck,pwz3n0/buck,Heart2009/buck,Addepar/buck,dsyang/buck,LegNeato/buck,artiya4u/buck,davido/buck,tgummerer/buck,Distrotech/buck,nguyentruongtho/buck,SeleniumHQ/buck,liuyang-li/buck,ilya-klyuchnikov/buck,ilya-klyuchnikov/buck,bocon13/buck,Dominator008/buck,siddhartharay007/buck,robbertvanginkel/buck,zhan-xiong/buck,mnuessler/buck,hgl888/buck,JoelMarcey/buck,MarkRunWu/buck,vine/buck,LegNeato/buck,davido/buck,rmaz/buck,sdwilsh/buck,LegNeato/buck,liuyang-li/buck,grumpyjames/buck,mnuessler/buck,k21/buck,illicitonion/buck,artiya4u/buck,vine/buck,OkBuilds/buck,shs96c/buck,k21/buck,dushmis/buck,davido/buck,rowillia/buck,JoelMarcey/buck,daedric/buck,dpursehouse/buck,Learn-Android-app/buck,stuhood/buck,Addepar/buck,vschs007/buck,shybovycha/buck,brettwooldridge/buck,OkBuilds/buck,pwz3n0/buck,Distrotech/buck,LegNeato/buck,1yvT0s/buck,daedric/buck,siddhartharay007/buck,k21/buck,stuhood/buck,sdwilsh/buck,Distrotech/buck,dushmis/buck,robbertvanginkel/buck,grumpyjames/buck,Dominator008/buck,nguyentruongtho/buck,neonichu/buck,facebook/buck,raviagarwal7/buck,luiseduardohdbackup/buck,darkforestzero/buck,rmaz/buck,illicitonion/buck,mread/buck,kageiit/buck,Heart2009/buck,janicduplessis/buck,zhuxiaohao/buck,janicduplessis/buck,zhan-xiong/buck,neonichu/buck,brettwooldridge/buck,vschs007/buck,zhan-xiong/buck,dushmis/buck,zhan-xiong/buck,hgl888/buck,rmaz/buck,zhuxiaohao/buck,clonetwin26/buck,kageiit/buck,Addepar/buck,mnuessler/buck,mread/buck,vschs007/buck,dushmis/buck,rowillia/buck,clonetwin26/buck,Dominator008/buck,janicduplessis/buck,rowillia/buck,tgummerer/buck,mread/buck,siddhartharay007/buck,tgummerer/buck,clonetwin26/buck,nguyentruongtho/buck,hgl888/buck,raviagarwal7/buck,stuhood/buck,artiya4u/buck,bocon13/buck,grumpyjames/buck,Heart2009/buck,bocon13/buck,zhan-xiong/buck,shs96c/buck,shybovycha/buck,pwz3n0/buck,brettwooldridge/buck,stuhood/buck,ilya-klyuchnikov/buck,brettwooldridge/buck,clonetwin26/buck,LegNeato/buck,Addepar/buck,OkBuilds/buck,OkBuilds/buck,artiya4u/buck,shs96c/buck,lukw00/buck,justinmuller/buck,Dominator008/buck,lukw00/buck,artiya4u/buck,k21/buck,mikekap/buck,shybovycha/buck,sdwilsh/buck,neonichu/buck,Dominator008/buck,sdwilsh/buck,liuyang-li/buck,artiya4u/buck,darkforestzero/buck,rhencke/buck,ilya-klyuchnikov/buck,mikekap/buck,rmaz/buck,illicitonion/buck,shybovycha/buck,SeleniumHQ/buck,brettwooldridge/buck,mread/buck,robbertvanginkel/buck,raviagarwal7/buck,janicduplessis/buck,shs96c/buck,marcinkwiatkowski/buck,rhencke/buck,lukw00/buck,mogers/buck,Heart2009/buck,daedric/buck,artiya4u/buck,darkforestzero/buck,sdwilsh/buck,grumpyjames/buck,OkBuilds/buck,daedric/buck,dsyang/buck,zhuxiaohao/buck,lukw00/buck,SeleniumHQ/buck,marcinkwiatkowski/buck,pwz3n0/buck,darkforestzero/buck,saleeh93/buck-cutom,rhencke/buck,k21/buck,romanoid/buck,hgl888/buck,1yvT0s/buck,zpao/buck,luiseduardohdbackup/buck,shybovycha/buck,rhencke/buck,vschs007/buck,zhan-xiong/buck,shs96c/buck,grumpyjames/buck,janicduplessis/buck,illicitonion/buck,k21/buck,lukw00/buck,mogers/buck,rhencke/buck,tgummerer/buck,davido/buck,zhan-xiong/buck,Heart2009/buck,darkforestzero/buck,shs96c/buck,grumpyjames/buck,justinmuller/buck,neonichu/buck,shs96c/buck,artiya4u/buck,vschs007/buck,liuyang-li/buck,saleeh93/buck-cutom,luiseduardohdbackup/buck,luiseduardohdbackup/buck,romanoid/buck,JoelMarcey/buck,marcinkwiatkowski/buck,darkforestzero/buck,janicduplessis/buck,daedric/buck,sdwilsh/buck,illicitonion/buck,Distrotech/buck,mikekap/buck,k21/buck,dsyang/buck,vine/buck,zhuxiaohao/buck,darkforestzero/buck,lukw00/buck,OkBuilds/buck,romanoid/buck,clonetwin26/buck,artiya4u/buck,vschs007/buck,zhan-xiong/buck,raviagarwal7/buck,Heart2009/buck,kageiit/buck,MarkRunWu/buck,zpao/buck,Addepar/buck,dpursehouse/buck,vine/buck,robbertvanginkel/buck,bocon13/buck,stuhood/buck,k21/buck,ilya-klyuchnikov/buck,siddhartharay007/buck,1yvT0s/buck,raviagarwal7/buck,dsyang/buck,zhan-xiong/buck,romanoid/buck,siddhartharay007/buck,mnuessler/buck,brettwooldridge/buck,brettwooldridge/buck,facebook/buck,saleeh93/buck-cutom,1yvT0s/buck,clonetwin26/buck,rmaz/buck,mikekap/buck,sdwilsh/buck,mogers/buck,Learn-Android-app/buck,romanoid/buck,daedric/buck,rmaz/buck,robbertvanginkel/buck,illicitonion/buck,k21/buck,dsyang/buck,Addepar/buck,tgummerer/buck,mikekap/buck,rmaz/buck,mnuessler/buck,dushmis/buck,saleeh93/buck-cutom,rowillia/buck,robbertvanginkel/buck,neonichu/buck,rhencke/buck,stuhood/buck,dpursehouse/buck,bocon13/buck,rmaz/buck,clonetwin26/buck,shybovycha/buck,JoelMarcey/buck,dushmis/buck,MarkRunWu/buck,daedric/buck,sdwilsh/buck,vschs007/buck,darkforestzero/buck,dushmis/buck,janicduplessis/buck,k21/buck,davido/buck,pwz3n0/buck,davido/buck,rowillia/buck,rowillia/buck,raviagarwal7/buck,marcinkwiatkowski/buck,dpursehouse/buck,lukw00/buck,rowillia/buck,romanoid/buck,Distrotech/buck,OkBuilds/buck,luiseduardohdbackup/buck,nguyentruongtho/buck,hgl888/buck,raviagarwal7/buck,grumpyjames/buck,vschs007/buck,grumpyjames/buck,stuhood/buck,janicduplessis/buck,vine/buck,dpursehouse/buck,luiseduardohdbackup/buck,clonetwin26/buck,shs96c/buck,robbertvanginkel/buck,kageiit/buck,raviagarwal7/buck,raviagarwal7/buck,facebook/buck,marcinkwiatkowski/buck,raviagarwal7/buck,Addepar/buck,mogers/buck,Learn-Android-app/buck,justinmuller/buck,pwz3n0/buck,LegNeato/buck,1yvT0s/buck,dushmis/buck,neonichu/buck,daedric/buck,Dominator008/buck,darkforestzero/buck,darkforestzero/buck,romanoid/buck,clonetwin26/buck,liuyang-li/buck,shs96c/buck,bocon13/buck,sdwilsh/buck,ilya-klyuchnikov/buck,ilya-klyuchnikov/buck,neonichu/buck,vschs007/buck,mogers/buck,darkforestzero/buck,Dominator008/buck,Learn-Android-app/buck,dpursehouse/buck,OkBuilds/buck,vschs007/buck,facebook/buck,Distrotech/buck,illicitonion/buck,siddhartharay007/buck,SeleniumHQ/buck,rhencke/buck,pwz3n0/buck,Addepar/buck,MarkRunWu/buck,marcinkwiatkowski/buck,marcinkwiatkowski/buck,stuhood/buck,rmaz/buck,zpao/buck,shs96c/buck,SeleniumHQ/buck,1yvT0s/buck,kageiit/buck,lukw00/buck,MarkRunWu/buck,Dominator008/buck,saleeh93/buck-cutom,MarkRunWu/buck,rhencke/buck,Heart2009/buck,mikekap/buck,dsyang/buck,tgummerer/buck,robbertvanginkel/buck,lukw00/buck,Distrotech/buck,LegNeato/buck,JoelMarcey/buck,mnuessler/buck,stuhood/buck,shs96c/buck,daedric/buck,OkBuilds/buck,JoelMarcey/buck,illicitonion/buck,neonichu/buck,zhan-xiong/buck,robbertvanginkel/buck,vine/buck,daedric/buck,pwz3n0/buck,illicitonion/buck,nguyentruongtho/buck,rmaz/buck,mikekap/buck,Dominator008/buck,Addepar/buck,Learn-Android-app/buck,romanoid/buck,siddhartharay007/buck,Addepar/buck